Patients requiring mechanical ventilation (MV) for more than 21 days account for more than 37% of all ICU costs. As such, these patients are now transferred to centers that specialize in weaning from MV, so called long-term acute care (LTAC) facilities. Despite the proliferation of LTAC facilities, research on tests that reliably identify which patients are likely to wean and methods for expediting weaning are lacking. In addition, little or no information is available regarding the determinants of survival, home discharge, and patient's perception of quality of life (QOL) after a prolonged course of MV. Thus, the aim of this proposal is to determine the most efficient way to wean patients who require prolonged MV (defined as >21 days) and have been transferred to an LTAC facility and to identify which patients are likely to wean from MV. The secondary aim is to determine the factors that predict survival and home discharge from a LTAC facility and the long-term impact of prolonged MV on functional status and QOL. To address these aims, a prospective, randomized trial in patients who are transferred to a LTAC facility will be done to compare the efficacy of two weaning techniques: pressure support and spontaneous breathing trials. Demographics, physiological, psychological, and general health status will also be measured to examine the accuracy of such measurements in predicting weaning outcome, survival, and home discharge. Respiratory muscles strength, handgrip strength, and their relationship to patient perception of functional status and QOL will be measured at the LTAC facility and the patient place of residence at 6 and 12 months after discharge. Findings from this proposal will provide novel insights into the most reliable means for predicting which patients can wean and survive to be discharged home, the most efficient method of weaning patients, and the impact of prolonged MV on long-term QOL and functional status. Such information will provide for the first time solid scientific evidence to health care providers, and help them formulate objective guidelines for the management of patients being weaned at a LTAC facility. [unreadable] [unreadable]